Function cc_conn_init

freebsd/netinet/tcp_input.c:383–437

}

void
cc_conn_init(struct tcpcb *tp)
{
	struct hc_metrics_lite metrics;
	struct inpcb *inp = tp->t_inpcb;
	u_int maxseg;
	int rtt;

	INP_WLOCK_ASSERT(tp->t_inpcb);

	tcp_hc_get(&inp->inp_inc, &metrics);
	maxseg = tcp_maxseg(tp);

	if (tp->t_srtt == 0 && (rtt = metrics.rmx_rtt)) {
		tp->t_srtt = rtt;
		tp->t_rttbest = tp->t_srtt + TCP_RTT_SCALE;
		TCPSTAT_INC(tcps_usedrtt);
		if (metrics.rmx_rttvar) {
			tp->t_rttvar = metrics.rmx_rttvar;
			TCPSTAT_INC(tcps_usedrttvar);
		} else {
			/* default variation is +- 1 rtt */
			tp->t_rttvar =
			    tp->t_srtt * TCP_RTTVAR_SCALE / TCP_RTT_SCALE;
		}
		TCPT_RANGESET(tp->t_rxtcur,
		    ((tp->t_srtt >> 2) + tp->t_rttvar) >> 1,
		    tp->t_rttmin, TCPTV_REXMTMAX);
	}
	if (metrics.rmx_ssthresh) {
		/*
		 * There's some sort of gateway or interface
		 * buffer limit on the path.  Use this to set
		 * the slow start threshold, but set the
		 * threshold to no less than 2*mss.
		 */
		tp->snd_ssthresh = max(2 * maxseg, metrics.rmx_ssthresh);
		TCPSTAT_INC(tcps_usedssthresh);
	}

	/*
	 * Set the initial slow-start flight size.
	 *
	 * If a SYN or SYN/ACK was lost and retransmitted, we have to
	 * reduce the initial CWND to one segment as congestion is likely
	 * requiring us to be cautious.
	 */
	if (tp->snd_cwnd == 1)
		tp->snd_cwnd = maxseg;		/* SYN(-ACK) lost */
	else
		tp->snd_cwnd = tcp_compute_initwnd(maxseg);

	if (CC_ALGO(tp)->conn_init != NULL)
		CC_ALGO(tp)->conn_init(tp->ccv);
}

void inline
cc_cong_signal(struct tcpcb *tp, struct tcphdr *th, uint32_t type)